My first Magazine Sky & Telescope - 02.2019

FEBRUARY 2019 OBSERVING Deep-Sky Wonders N wind from the extremely hot star along the 2’s inner curve pounding against a surrounding molecular cloud. The star is about 12,000 light-years distant and will only survive for an astronomically brief time before it destroys itself in a spectacular supernova explosion. One of my favorite sights in Canis Major is NGC 2362, also named the Tau Canis Majoris Cluster for its brightest star. This is a pretty cluster even at 23× in the 130-mm scope, showing radi- ant Tau (τ) closely guarded by several lesser lights. It becomes quite lovely at 102×, with 25 stars, including one very near Tau, drawn to Tau like moths to a ﬂame. The gathered moths envelop Tau within a triangle whose narrow- est corner points south-southwest, and several strays trail northward from the triangle’s base. At 164× I count 30 stars spanning 9′, none close to rivaling Tau’s blue-white splendor. The 10-inch scope at 171× teases out 45 stars and brings to mind a dazzling brooch with Tau as the showpiece jewel. NGC 2362 is a very young star cluster. According to the WEBDA data- base ( univie.ac.at/webda ), it’s about 8 million years old and 4,500 light-years away from us. While in the neighborhood of NGC 2362, I like to climb 1.7° north- northwest to drop in on the optical double star h3945 (HJ 3945). This is a much-loved pair for many amateur astronomers, who often compare it to summer’s Beta (β) Cygni by call- Near the Dog Star Object Type Mag(v) Size/Sep RA Dec. Sirius Double star −1.5, 8.4 11.1″ 6 h 45.1 m −16° 43′ M41 Open cluster 4.5 39′ 6 h 46.0 m −20° 45′ NGC 2359 Bright nebula ~10½ 9′ × 6′ 7 h 18.5 m −13° 14′ NGC 2362 Open cluster 3.8 6′ 7 h 18.7 m −24° 57′ h3945 Double star 5.0, 5.8 26.4″ 7 h 16.6 m −23° 19′ Emission nebula — 9′ × 8′ 7 h 09.9 m −18° 30′ Sh 2-301 Angular sizes and separations are from recent catalogs. Visually, an object’s size is often smaller than the cataloged value and varies according to the aperture and magnifi cation of the viewing instrument. Right ascension and declination are for equinox 2000.0. 56 FE B RUA RY 2 019 • SK Y & TELESCOPE ing it the Winter Albireo. Through my 105-mm refractor, the stars are widely separated at 28×. The primary star looks ﬁrelight-gold, but the companion doesn’t appear to have the blue-white glow I see in the companion to Albireo. Instead, I usually perceive it as white, sometimes with a touch of yellow. What colors do you see? Let’s ﬁnish our tour with the seldom- visited emission nebula Sharpless 2-301, centered 12′ north-northwest of the 6th-magnitude star HD 54958 (HIP 34617). Sh 2-301 is easy to pick out with a narrowband ﬁlter using the 130- mm scope at 37×. It appears vaguely roundish and harbors one faint star. The ﬁlter is unnecessary at 102×, and the nebula grows irregular in bright- ness with 3 stars nested in the most conspicuous part. A star 2.3′ southwest of the trio inhabits a dimmer area of the nebula’s main mass, which sprawls across 5′. Diaphanous mist wafts north from the 5′ mass and fades away a bit before reaching a tight little arc of three stars. A 10th-magnitude star marks the nebula’s southeastern edge, accompa- nied by a yellow, 7th-magnitude gem farther out. Give this little-known wonder a try! ¢ Contributing Editor SUE FRENCH vis- its the realm of the Dog Star as often as possible in the winter observing season. M p Left: The bright nebula Sharpless 2-301 resembles an irregular triangle in the eyepiece, with three stars embedded in the brightest part. This sketch shows the view through a 14.5-inch f/3.8 reflector at 118×. Right: Giovanni Hodierna discovered the open cluster NGC 2362 before 1654; it was inde- pendently (re)discovered by William Herschel in 1783. This young cluster includes about 60 stars.

My first Magazine Sky & Telescope - 02.2019 | Page 58